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Section 3 Seed reproduction.

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Presentation on theme: "Section 3 Seed reproduction."— Presentation transcript:

1 Section 3 Seed reproduction

2 pollen Spores develop in pollen grains Has water resistant covering
Male sperm Transfer to female part by wind, gravity, water and animals Creates pollen tube when reaches female part. Sperm moves thru tube to ovary

3 seeds Develop after fertilization
Has food source (embryo) and a seed coat for protection Embryo produces stems, roots, and leaves New plants develop faster from seeds than spores Gymnosperms and angiosperms are seed plants. Gymno. produce seeds in cones, angio. in flowers and fruit

4 Gymnosperm reproduction
Cones are repro. structures Include pines Produce male and female cones Egg is produced in ovule in spring, male cones release clouds of pollen to fertilize female cones

5 Gymnosperm seeds Pollen falls on female cone and can take 2 to 3 years for seeds to be released

6 Angiosperm reproduction
Most earth plants today are angio. All have flowers (reproductive organs) Flowers produce sperm and egg

7 The flower Four main parts-petals, sepals, stamen and pistil
Colorful parts are petals Sepals cover the bud Stamen is male repro. part Pistil is female part containing swollen ovary at its base Not all flowers have all 4 parts


9 Importance of flowers Large, colorful flowers attract insects and other animals. Pollen sticks to them and is moved around Some plants depend on wind and water to spread pollen

10 Angiosperm seeds Flower is pollinated when pollen reaches the stigma and a pollen tube forms allowing the pollen to reach the ovule and fertilize the egg A zygote forms and grows into a plant embryo

11 Seed development Part of ovule develops into the stored food (cotyledon) and seed coat

12 Seed dispersal Most seeds grow only when placed in soil
Gravity pulls seeds to ground Carried great distances by wind, water and animals

13 germination Events that result in the growth of a plant from a seed
Some germinate and some can stay in resting stage for hundreds of years Seeds only germinate when conditions are right Water absorption causes germination

14 Energy is released from cotyledon and a root grows followed by stems and leaves
Photosynthesis takes over

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